It is common in electronic product manufacturing processes to want to test production components on a volume basis. This testing is quite important when the component is a circuit card. The performance of the product (such as a computer or related peripheral) in which the card is to be installed is dependent on accurate processing of signals and data by the circuitry on the card.
Testing of such cards is normally accomplished in a production environment by successively placing cards to be tested in a test fixture. The card connects to test circuitry via the fixture. The card typically makes contact with the test fixture through a connector. This connector is typically a female portion on the test fixture disposed to receive pins located on and extending from the card.
Mechanisms in the prior art to engage the card both physically and electrically in the test fixture suffer from a number of disadvantages. Prior solutions include a fixed male/female connector into which the operator inserts and removes the circuit card assembly. This solution requires excessive forces by the operator, and engagement and release is often accompanied with a back and forth "wiggle" motion which can damage the connector. This damage reduces the life of the female portion of the connector in the test fixture, as well as impairing the pin configuration of the card itself prior to installation in a product. Another prior art solution includes a large linkage mechanism in which is difficult maintain appropriate tolerances and is cumbersome to include in a system solution.
Prior art mechanisms also favor mechanical thumb levers for the operator to release the card. A problem with thumb levers is that if they are not released at the same time, removal of the card can exert a torsional motion on the card that in turn bends the pins on the mating connector. Thumb levers in the prior art also do not necessarily physically engage and hold the card itself. Installing and removing the card from the test thus becomes a two- or three-step process: electrical engagement via a connector held with thumb levers and then physical engagement by other means. This can cause excessive time in a production testing environment to be used just taking one card out of the test fixture and putting another one in.
There is therefore a need in the art for a single action engagement mechanism for inserting and removing cards in and out of housings such as test fixtures. The engagement should be concurrently physical and electrical, advantageously in one motion. The mechanism in operation should cause minimal bending stress to connector pins. The mechanism should also be simple to manufacture and install, while still being reliable over a long maintenance interval.